Alfa Romeo Stelvio Forum banner

1 - 15 of 15 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter #1
Hey all,

I am thoroughly enjoying my Stelvio.... drives great! Just wondering if anyone else has a little more understanding of the slight turbo lag the car has when flooring it from a stop. It appears that all engines especially turbo chargers have a slight lag to them. The turbo once it comes in certainly makes up for that lag. Do cars with more torque tend to produce less lag from the onset of flooring it? What type of turbo-charger does the Stelvio have? Is it clutched?

Matt
 

·
Registered
Joined
·
1,797 Posts
You want to launch off the line you need to brake tq. Just put left foot on brake, depress gas a little and it will be spooled up ready to fly!!
 
  • Like
Reactions: wassei1

·
Premium Member
2018 Stelvio Base 20" yellow calipers
Joined
·
1,504 Posts
The motivation for the turbocharger impeller is exhaust gasses from combustion. At idle or low RPM's the volume of exhaust isn't enough to spin the rotor and there is a slight delay as the pressure builds that forces air into the intake and Stelvio goes zoom zoom. It is an efficient way to get more power out of a small displacement engine that delivers great fuel economy between bursts of power but the tradeoff is excess heat, one of the compromises and the slight delay referred to as turbo lag while all of this spools up from a stop.

Superchargers, belt driven, are an option but much of the boost is wasted and they use power even when not needed. Fast drivers hold the brake, spool up to about 2500 RPM and launch from that head start. Underway, boost is more available.

All that to say the options are larger displacement (Hellcat or Hemi + added weight) or accept the slight compromise that has been all but engineered out by our dear Italian friends.

I had a couple of the 2.2 early Chrysler non-intercooled turbos and loved them back in the day when the Lancer was the early A6 alternative. So in a big way, it really is about getting used to a different motivation. The benefit is best of power when needed + fuel economy to address the current times.

Hope you come to appreciate + enjoy the tech.
 
  • Like
Reactions: wassei1 and FOURCED

·
Read Only
Joined
·
849 Posts
Stelvio have a twin scroll turbo Garrett, 848460-0001 part number of Chrysler

It is not a variable geometry but have the wastgate electronically controlled with good performance.

Under 1700rpm the performance are not great but acceptable. Max turbo pressure is 1.6 bar stock.
 

·
Premium Member
2018 Stelvio Base 20" yellow calipers
Joined
·
1,504 Posts
As always- thanks, Marzio!
 

·
Registered
Joined
·
2,643 Posts
I had one of these when it came out - the article says small low inertia turbo to reduce lag, but that must have been compared to a 76 porsche turbo.
It was terrible, you had to seriously plan ahead to pass cars, and I swore I would never get another turbo anything (or fwd). I'd much rather have a high revving naturally aspirated engine.

so here I am waiting for a twin turbo, but I do think the lag is much less than turbos used to have, and it's the only way to get performance while meeting government fuel economy standards.
and I do stand corrected on the creators of start/stop technology, it was europe - but I think cadillac had the 4-6- 8 before anyone? so there are a few "innovations" coming on my new car I'm not pleased about, but it's the whole package, and brake starts are nothing new, it's been SOP for US drag racing forever.
 

·
Registered
Joined
·
10 Posts
Discussion Starter #8
Hey yeah that should do the trick! Where it doesn't work as well is when you are slowing to a stop and then quickly trying to gun it again when on a busy road. 2 things that appear to be working to dealing with the lag in this type of situation is slowing down but not stopping and then using paddle shifters to shift to a lower gear. If not using the shifters, then pressing the gas part of the way seems to pick up quicker than flooring it. Thanks for the response.
 

·
Read Only
Joined
·
849 Posts
The new way for a nolag turbo is hybrid turbo, electric + gas or the more expensive way from porsche variable geometry on petrol engine turbo. Alternative but more complicated, twin serial push turbos or 3 turbos sequential .
Old old old solution, volumetric turbo
 
1 - 15 of 15 Posts
Top